/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.core;



import com.bff.gaia.unified.sdk.options.PipelineOptions;

import com.bff.gaia.unified.sdk.transforms.CombineFnBase.GlobalCombineFn;

import com.bff.gaia.unified.sdk.transforms.windowing.BoundedWindow;



import java.io.Serializable;

import java.util.Collection;



/**

 * An interface that runs a {@link GlobalCombineFn} with unified APIs.

 *

 * <p>Different combine functions have their own implementations. For example, the implementation

 * can skip allocating {@code Combine.Context}, if the combine function doesn't use it.

 */

public interface GlobalCombineFnRunner<InputT, AccumT, OutputT> extends Serializable {

  /**

   * Forwards the call to a {@link GlobalCombineFn} to create the accumulator.

   *

   * <p>It constructs a {@code CombineWithContext.Context} from {@link PipelineOptions} and {@link

   * SideInputReader} if it is required.

   */

  AccumT createAccumulator(

	  PipelineOptions options,

	  SideInputReader sideInputReader,

	  Collection<? extends BoundedWindow> windows);



  /**

   * Forwards the call to a {@link GlobalCombineFn} to add the input.

   *

   * <p>It constructs a {@code CombineWithContext.Context} from {@link PipelineOptions} and {@link

   * SideInputReader} if it is required.

   */

  AccumT addInput(

	  AccumT accumulator,

	  InputT value,

	  PipelineOptions options,

	  SideInputReader sideInputReader,

	  Collection<? extends BoundedWindow> windows);



  /**

   * Forwards the call to a {@link GlobalCombineFn} to merge accumulators.

   *

   * <p>It constructs a {@code CombineWithContext.Context} from {@link PipelineOptions} and {@link

   * SideInputReader} if it is required.

   */

  AccumT mergeAccumulators(

	  Iterable<AccumT> accumulators,

	  PipelineOptions options,

	  SideInputReader sideInputReader,

	  Collection<? extends BoundedWindow> windows);



  /**

   * Forwards the call to a {@link GlobalCombineFn} to extract the output.

   *

   * <p>It constructs a {@code CombineWithContext.Context} from {@link PipelineOptions} and {@link

   * SideInputReader} if it is required.

   */

  OutputT extractOutput(

	  AccumT accumulator,

	  PipelineOptions options,

	  SideInputReader sideInputReader,

	  Collection<? extends BoundedWindow> windows);



  /**

   * Forwards the call to a {@link GlobalCombineFn} to compact the accumulator.

   *

   * <p>It constructs a {@code CombineWithContext.Context} from {@link PipelineOptions} and {@link

   * SideInputReader} if it is required.

   */

  AccumT compact(

	  AccumT accumulator,

	  PipelineOptions options,

	  SideInputReader sideInputReader,

	  Collection<? extends BoundedWindow> windows);

}